Firetrap for motion picture projectors



Aug. 5, R EN 2,251,704

FIRETRAP FOR MOTION PICTURE PROJECTORS Filed Jan. 31, 1939 I5 Sheets-Sheet l INVENTOR. Al oberi-a 9-rench @M P ALLWU A Ti 'ORN E YS' 1941- R. R. FRENCH 2,251,704-

FIRETRAP FOR MOTION PICTURE PROJECTORS Filed Jan. 31, 1939 3 Sheets-Sheet 2 INVENTOR. $011914 9='ren ch ATTORNEYS Aug. 5, 1941. R. R. FRENCH 2,251,704

FIRETRAP FOR MOTION PICTURE PROJECTORS Filed Jan. 31, 1939 3 Sheets-Sheet 5 fi l/11111111111, r fi in 7/1/1 [WI/III 2 p v ATTORNEYS Patented Aug. 5, 1941 FIRETRAP FOR MOTION PICTURE PROJECTORS Robert R. French, New York, N. Y.

Application January 31, 1939, Serial No. 253,721

2 Claims.

maintain. The principle of the fire valve construction of my present invention provides a narrow compound sinuous path for the film, rapidly changing in direction to enhance the fire extinguishing properties of the valve. In

the preferred construction I employ two sym- 1 metrically arranged roller arrangements to provide a long intermediate portion for the sinous path positioned angularly with respect to the normal film travel to and from the valve. The valve assembly is formed with a view towards long wear, ease of cleaning and ready replacement.

Another important feature of my invention resides in the safety arrangement preventing the closure of film reels or other major portions of the projecting machine before the valve is sealed. The valve covers are designed to abut the projection unit covers except when looked upon the valve. Further arrangements for the valve cover insure positive interlocking and sealing of the projection unit including the valve.

These and further objects of my present invention will become apparent in the following description of a preferred construction thereof, taken in connection with the drawings, in which:

Figure 1 is a side view partly broken away of a projection machine employing the valves of my present invention.

Figure 2 is a side view of the upper valve with the door open.

Figure 3 is an end view of the upper valve with the door closed.

Figure 4 is a cross-sectional view taken along l-4 of Figure 3 vertically through the upper valve unit.

Figure 5 is a broken away horizontal sectional view taken along 5-5 in Figure 4 through the valve.

Figure 6 is a broken vertical cross-sectional view through the valve taken along 6-6 of Figure 4.

Figure '7 is a side view of the lower valve with the door open.

Figure 8 is an end view of the lower valve.

Figure 9 is a vertical cross-sectional view and onto the take-up reel 2'1.

through the valve taken along 9--9 of Figure 8.

Figure 10 is a broken vertical sectional view through the lower valve as taken along Ill-l0 of Figure 9.

Figure 11 is a broken horizontal sectional view through the valve taken along H-l| of Figure 9.

The projection machine unit 19 shown in Figure 1 is of the conventional type provided with a door 20 and contains an upper magazine 2| for the motion picture film. The feed reel 23 carrying the film 25 is normally adjusted in the upper magazine 2| and the take-up reel 24, in the lower magazine 22 as is evident to those skilled in the art. The inflammable film 25 is threaded through the upper fire-valve 25, through the sprocket arrangements internal of the projection unit, l9, through the lower fire valve 21 For purposes of showing the ingress and egress of the film 25 through the projection machine unit IS, the door 20 therefore is shown with cut-away portions at these points.

The fire valves 26 and ill of my present invention are designed to prevent any possibility of flame or burning film being communicated between the projection chamber is, and the upper and lower magazines 2i and 22. They are interjected between the magazines containing the film reels and the projection chamber [9. The magazines are supported entirely by arm casting attached to the back of the magazines. Fire traps 26 and 21 are of such design and structure that they can be readily installed on present motion picture projectors in place of the present inadequate fire valves. Details of the novel features of the fire valves 25 and 2'! will be hereinafter described in more detail in connection with Figures 2 to 11.

The upper fire valve 26 is provided with a hinged door 28 designed so as to seal the film path through the valve 26 after the film is properly threaded therethrough. An explosionproof latch 29 afiixed to the side of the valve 26 coasts-with valve door 28 to tightly hold the door against the valve. Similarly a valve door 3% is provided for the lower valve 21 coacting with explosion proof latch 3! to seal the valve.

Another important feature of the first valves of my invention resides in the construction of the valve doors 28 and 30 to prevent their remaining open after the remainder of the projection unit and magazines are covered or sealed. Thus fire-valve door 28 will prevent the closing of the projector door 23 and lower fire-valve door will prevent the closing of lower magazine cover 33 unless the respective fire-valve doors 28 and 30 are closed first. Projector door 20 when being closed automatically closes firevalve door 28. This is an important safety feature which prevents oversight and insures sealing of all the units containing the inflammable film.

The valve structures are preferably curved to conform with the portion of the cylindrical magazines they are secured to. It is obvious that where square magazines are employed the valve structures are designed to conform to their shape. Cover 28 of upper fire-valve 26 conforms to the shape of valve 26 particularly in the upper surface 34 thereof. The edge 34 of cover 28 is shown arcuate and having a substantial curvature to conform to the shape of the magazine cover 32, the edge 34 abutting the beaded edge of the magazine door 32. 23 is open, the raised curved portions towards the knob end of the curved edge 34 adjacent the hinge of door 28 will abut cover 32 if an attempt to close the magazine door 32 upon magazine 2| is made. Thus in order to close the magazine door 32 it is first necessary to close the valve door 28 and the operator is always apprised thereof. This feature may also be reversed as the projection 37 may be so designed as to assure closing of the magazine door 32 first, the projection 31 pressing against the lower front edge of magazine door 32, should fire-valve door 28 be closed first, the projection 3'! will prevent the magazine door 32 from closing. This is an added feature and insures the closing of all doors in progressive stages and provides additional locking and sealing of film compartments. In a similar manner, the lower valve cover, 35 having the arcuate or otherwise extended edge 35 prevents the closure of lower magazine cover 33 until the fire-valve door 3|] is closed thus assuring that the fire-valve 27 is sealed.

In order to further insure sealing of the fire trap and contiguous units I provide projections 36, 3'! on upper fire corresponding recesses adjacent thereto in the fire-valve. The projection 36 is lower than the top of door cover 20 and therefore 28 and 28 close together and stay closed together. Thus when the door 28 of the projection unit I9 is closed, corresponding sealing of valve 26 is insured. Similarly I provide protuberances 38 and 39 from valve door 30 covering the recesses for the adjacent rollers and fitting of the valve 21 which project into the magazine 22 for interlocking and sealing the valve when magazine cover 33 is closed and prevent closing door 33 without having first closed 36.

Figure 2 is an enlarged front view of the upper fire-valve 26. I provide a novel positive fire extinguishing arrangement for valve 26 comprising a pair of input rollers 40 and 4|, and a narrow sinuous path 42-43-44 for film 25 which emerges from valve 26 between coacting rollers and 46. Large intermediary guide rollers 41 and 48 are placed at the bent-over portions of the sinuous path of the film to accurately guide and maintain the film in the path and prevent scraping or contacting of the film with the stationary path 42-43-44.

An important feature of my present invention resides in the arrangement and construction of the sinuous path 42-43-44, and the associated guiding means for the film therein. The thickness of the film path within valve 26 is made When fire-valve door door 28 to interlock with as narrow as practicable to exclude as much contained air in the path as feasible. The dearth of air within the valve is an important factor in reducing the spread of fiame within the unit and serves in combination with the further features hereinafter described to promptly extinguish an ignited film therein.

Another important feature in my fire-valve resides in the substantial length and inclination of the intermediate portions 42-43 and 44 of the sinuous film path. In the event that film remains ignited beyond the initial path section 44 and roller 48, it would be necessary for the flame to travel downward through the oblique path 43. The length and angular position of path 43 greatly inhibits any downward movement of the flame and is a great deterrent to the passage of the flame beyond this section. The intermediate rollers 41 and 48 are so arranged that the path of the film feed through the fire-valve becomes a sinuous path, the film ceding around a substantial part of the upper peripheral surface of one intermediate roller and around a substantial part of the lower peripheral surface of another intermediate roller. In fact, my experiments have shown that the ignited film is always extinguished before reaching roller 41 at the lower end of section 43.

The end view, Figure 3, of the upper fire-valve 26 shows the valve door 28 in position, locked by latch 29 and provided with a conventional knob 49.

Vertical cross-sectional view 4-4 of Figure 3 through the upper fire-valve 26 shown in Figure 4 further illustrates advantageous features of my preferred construction and arrangement. The body 50 of the fire-valve is a metallic casting containing pockets 5| to reduce its weight. The film path 42-43-44 is cast directly within the body 50, as is the spaces for the respective guidc rolls 46-4I and 45-46 and the intermediary rollers 47-48 for the film. The respective rollers 40, 4|, 45, 46, 4'! and 48 are rotatably mounted in these spaces within the body 50.

Cross sectional views 5-5 and 6-6 of Figiue 4 through the fire valve 26 detailed in Figures 5 and 6 respectively show the manner in which the rollers are mounted. Rods 52 acting as shafts for the rollers 40, 4|, 45, 46, 41 and 48 are fixed to the rear wall of casting 50. The rear end of rods 52 are secured in position by nuts 54 or may be threaded into the main casting 50 in place of the nuts 54 or be knurled and force fitted into the casting. The guiding and intermediary rollers are rotatably mounted upon rods 52. Figure 5 shows the large intermediate rollers 4'! and 48 in position. The front of the casting is covered by metal plates 53a and 53b which may be cast or stamped to the desired shape. The plate 53a covers the guide roller 40, the pocket 5| in the casting above the roller 41, the pocket 5| below the film path 43, the intermediary roller 48 and the guide roller 45. The plate 53b covers the guide roller 4!, the pocket 5| above roller 48, the pocket 5| above the film path 43, the intermediary roller 41, the pocket below roller 48 and the guide roller 45. Suitable screws 56 are used to fasten front plates 53a and 53b against casting 50 leaving only the sinuous film paths 42, 43 and 44 visible when the door 28 of the valve is opening facilitating ease of threading. The front end of the rods 52 may be terminated into holes in these plates 53a and 53b to insure alignment and strengthen shafts. The plate 53b may also be used as the hinge portion for the valve door 28. Structural changes can obviously be made in the assembly without departing from the invention.

All of the rollers are equal in width to the film 25. The intermediate portion of the rollers are undercut to prevent scraping or contacting the image portion of the film as is well known in the art. The sprocket edge portions of the film rests upon the raised sides of the rollers and is properly guided thereby. It will be evident that the preferred arrangement of the valve of my present invention simplifies its construction with a particular view towards servicing, cleaning or simple replacement of any component thereof. The bushings 55 or other bearing surfaces are made of bronze to minimize wear; in place thereof oilless type of bearings well known may be used. Such bearings furthermore reduce any possible friction to a minimum and retain rollers in positive alignment.

The lower fire-valve 21 is illustrated in detail in Figures 7 to 11, inclusive. Figure '7 is an enlarged front view thereof. The general arrangement of the film path and the rollers and construction of the lower fire-valve 21 is similar to that already described in connection with the upper fire-valve 26. The lower surface 60 of the fire-valve 21 is arcuate for juxtaposition with the lower magazine 22 as already described and shown in Figure 1, and may be changed to fit any other shape of magazine as is obvious. The rollers of the lower valve comprise the input rollers iii-62, larger intermediate rollers 63-64 and output rollers 6566. Input rollers 6l-62 are mounted on a projecting portion 61 of the fire-valve, which portion projects directly into the projection chamber 20 as shown in Figure 1. The path for the film 25 defined by rollers 6| to 66 provides a sinuous path therefor consisting of film path sections 68, 69 and 10 and has the general conformation as that already described in connection with the upper firevalve 26.

Figure 8 shows an end view of the fire-valve 2i. latch 3|.

Figures 9, l and 11 are cross sectional views through the lower fire-valve 21 to illustrate the preferred physical construction thereof. Casting 15 contains pockets it, the sinuous film path 686910 and the spaces for the rollers GI to 66 inclusive. The rollers 6| to 66 are mounted on shafts 11 in a manner similar to that described in connection with the upper fire-valve illustrations. The front plates 18a and 18b for covering the main casting 15 to the right and left respectively of the sinuous film paths 68, 69 and are secured by screws '19 to casting and serves to properly align the roller shafts II and covers the pockets leaving an easily visible film path for threading. The rollers of the lower fire-valve are identical in construction to those described in connection with the upper firevalve 26.

It is to be understood that the film contacts the rollers throughout its passage through the valve of my invention and the rollers are so positioned that the film normally passes centrally through the narrow sinuous path provided without contacting the walls thereof. Ignited film curls and thereby contacts the surface causing a curled deposit of ash against the walls of the sinuous path, which assists greatly the extin- The door 39 has a knob H and is locked by guishing of the ignited film. In passing around the curves of the sinuous path in valve 21, the film is whipped or slapped against the walls depositing the ash therefrom in the path further cutting off the supply of air to the already reduced air chamber formed by the Walls in the sinuous film path resulting in rapidly extinguishing an ignited film. In Figure 1, when film 25 is cut off as, for example, beyond roller 40, it is no longer being pulled down by the sprocket and therefore rel rains stationary in upper valve 26- whereas in valve 21 the film. is pulled by take-up reel 24. The feature of my invention is not based on the conductivity of heat, by the metal parts of the fire-valves, from the ignited film. This is not a factor in my invention which is based on a fire-valve having the property of snufiing out the ignited film by passing the ignited film through a sinuous narrow path sealed against air and so arranged to alter the direction of travel of the film therethrough. Another factor is the sealed and confined arrangement of the valve and the minimum provision of available air to the relatively long sinuous or compound curved film path therein.

Although I have shown preferred arrangements for carrying out my present invention, it is to be understood that modifications are feasible therein which fall within the broader spirit and scope of the invention and accordingly I do not intend to be limited except as set forth in the following claims.

I claim:

1. A valve for a film roll for a motion picture film projection device comprising a body portion having a narrow all enclosed compound curved film path therein, film engaging rollers at each terminal of said path, a roller arranged with its peripheral surface coinciding with a curved portion of said film path to guide the film intermediate of said terminals of said path, a second roller arranged opposite said first roller with its peripheral surface coinciding with a second curved portion of said path, the uppermost point of the periphery of said second roller being above the lowermost periphery of said first roller so that the section of said path extending between said rollers is inclined upwardly from said first to said second roller and in an opposite direction with respect to the direction of movement of the film therethrough to obstruct the advance of a flame on the film.

2. A valve for a film roll for a motion picture film projection device comprising a body portion having a narrow all enclosed sinuous film path therein, film engaging rollers at each terminal of said path, a roller arranged with substantially more than half of its peripheral surface coinciding with a curved portion of said film path to guide the film intermediate of said terminals of said path, a second roller arranged opposite said first roller with substantially more than half of its peripheral surface coinciding with a sec-- ond curved portion of said path, the uppermost point of the periphery of said second roller being above the lowermost periphery of said first roller so that the section of said path extending between said rollers is inclined upwardly from said first to said second roller in an opposite direction with respect to the direction of movement of the film therethrough to obstruct the advance of a flame on the film.

ROBERT R. FRENCH. 

